CN114585799A

CN114585799A - Adjustable in situ, sealless and frangible downhole pressure control and isolation device and subassembly for conduits in a wellbore

Info

Publication number: CN114585799A
Application number: CN202080049463.0A
Authority: CN
Inventors: 康拉德·彼得罗夫斯基
Original assignee: Almo Tools International
Current assignee: Almo Tools International
Priority date: 2019-05-06
Filing date: 2020-05-06
Publication date: 2022-06-03
Also published as: US20220090465A1; CA3118601C; US11506017B2; US20240183246A1; US20230243237A1; US11933137B2; CA3118601A1; WO2020223815A1

Abstract

In wellbores that include tubulars, it is often desirable to isolate a portion of the pressure driven fluid flow path of the wellbore in the conduit section formed by the included tubulars to allow work to be done in the pressure control section of the flow path. The subassemblies and frangible devices provided herein achieve this with minimal exposure of the seal to the fluid environment of the well, and provide field-adjustable variability by removing the frangible seal from the flow path in which the subassembly is installed or included, by removing the differential pressure required to open the tubing.

Description

Adjustable in situ, sealless and frangible downhole pressure control and isolation device and subassembly for conduits in a wellbore

Background and Prior Art

Prior art frangible seal systems have been provided with frangible disks inserted inside subassemblies mounted in a column in a wellbore tubular. These subassemblies are not field adjustable and require disassembly and reassembly of the delicate (fragile) parts and seals to change the pressure response characteristics of the seal. For example, a new disc is required to replace the previous disc, which would involve disassembling the subassembly, removing the frangible disc and several O-rings and other seals, and then reassembling the subassembly with a new disc having different fracture and pressure control characteristics. Such disassembly and reassembly in the field without the introduction of rig test equipment or a controlled shop environment increases the risk of seal failure, which is undesirable and sometimes not permitted by the owner of the well.

Prior art inline pressure control systems having frangible disc seals are also typically formed from a subassembly of multiple body pieces joined together and include seals to ensure the integrity of the flow paths within the assembly. These seals are exposed to the wellbore fluid environment and therefore in some cases, if the wellbore fluid environment breaks the seal, the seal and subassembly need to be replaced and thus these subassemblies are not suitable for long term placement (whether sealed or broken) in the string of wellbores.

Some examples of prior art systems in this field are for example:

us patent application 15/829,696, provides a subassembly carried by a disc seal; and

US patent application US5924696, provides a disc-carrying subassembly.

US9593542 discloses a rupture disc held in place by a shear ring having separate sections which hold the rupture disc against sliding in the conduit of a tubing string. When sufficient pressure is applied to the convex side of the rupture disc, the shear ring separation section ruptures, causing the disc to slide and collide with the narrow section of pipe, thereby exerting inward radial pressure on the disc, causing the disc to burst (NCS oilfield services). The shear ring is not field adjustable and the system does not provide a piston or mating ring feature.

The apparatus and subassembly of the present invention overcomes some of the deficiencies of the prior art and is therefore an improvement.

Disclosure of Invention

The present invention provides a field adjustable downhole apparatus for controlling pressure within a wellbore and a zone of associated tubing within the wellbore by selectively isolating one portion of the wellbore and associated tubing from another portion of the wellbore and associated tubing, having some or all of the following features:

1. a tubular body having a connection means enabling the body to be connected in line with an associated wellbore tubular;

2. a hollow piston slidably movable in the bore of the device body, the piston having a dynamic seal with the inner surface of the bore; the piston has features (lugs, holes, grooves) into which the locating means can extend or attach;

3. piston positioning means (which may be one or more shear pins that engage both the body of the device and the piston) that hold the piston in place until the pressure on one side of the piston exceeds a threshold pressure, wherein the piston is movable when the positioning means is released and slides within a cylinder formed by the inner bore of the device;

4. a frangible dome disk having a circular rim with a flange, the flange of the disk being disposed and sealed to one side of the piston, the disk body within the rim being exposed to the bore of the device body, dividing and dividing the bore into two volumes, each volume being in fluid communication with a wellbore tubular conduit connected to one side or the other of the device; the disc is subjected on each side of the disc to fluid pressure exerted by fluid in a wellbore pipe connected to that (respective) side of the device;

5. the dome disk has a weakening on its body, which is located between: the connection between the edge of the concave round top surface of the disc main body and the inner surface of the flange; and a circumferential groove having a circumference approximately equal to an inner diameter of the flange portion disposed in the vicinity of a position where an edge of the convex rounded top surface intersects with the outer surface of the flange;

6. a cutout provided on the flange in the inner hole of the device on one side of the disc, toward the direction in which the piston is slidable when the positioning means is released, wherein the cutout is shaped and positioned such that, in the case where the piston and the disc attached thereto move after the positioning means releases the piston, the disc surface in the flange strikes the cutout, thereby causing the disc to break upon impact, causing the inner hole of the device body to become a flow conduit and ending the division of the inner conduit of the tube; the cutter is a cylindrical metal shape that can be fitted with a fluid discharge port at or near the end of the cutter that strikes the disk to allow any fluid discharged by the movement of the piston to escape through the discharge port into the central bore of the fitting body without impeding the movement of the piston;

7. the disc is retained, sealed and attached to the piston by at least one lo-hi seal on one side of the disc between the piston and the flange of the disc, a vented center seat ring on the other side of the disc and an adapter ring threadedly attached to the device bore; the joint ring is provided with an inner opening, and the inner diameter of the joint ring is slightly larger than the outer diameter of the cutting piece;

8. alternatively, the body of the device may be in multiple parts that can be disassembled and reattached, whereby attachment of one part can retain and seal the disk, lo-hi seal, and vented center seat ring to the piston, while the connection between the parts of the body assembly functions as a mating ring;

9. upon rupture of the disc, the flange thereof is sandwiched between the outer surface of the cutter, the recessed inner surface of the bore and the radial surface of the mating ring, thereby preventing the portion of the frangible disc seal body from entering the conduit of the wellbore formed within the pipe; a thin-walled steel ring may be inserted into the disc flange and sized to allow the cutter to strike the disc body, but in addition to isolate the ceramic flange portion of the disc seal, which after disc rupture (by being struck by the cutter edge) captures and holds the ceramic flange portion away from the tube bore and the tube flow passage;

10. the positioning device is field adjustable without completely disassembling the downhole apparatus, by changing the amount of force applied to the positioning device before it releases the piston (by changing the number or composition of shear pins installed to hold the piston in position with the apparatus body, this can be done through an external port on the body or through the piston wall and into an internal port of the apparatus body); a shear pin (for example) may be inserted from the outer surface of the body and extend inwardly through the body and into a mating aperture (slot, bore) located on the radially outer surface of the piston; if inserted from the outside, the piston may be inserted and mechanically sealed to the body by friction (e.g., the pin may be slightly tapered to wedge into a mating hole of the body, deform and seal to the body by being forced into place); alternatively, the pin may be threaded, screwing into mating threads on the body wall and a groove or aperture on the piston;

11. a space or volume exists in the inner bore of the device into which the piston can move when sliding after release of the positioning means, the space or volume being outside the outer surface of the cutter and thus being bounded by the end of the piston remote from the disc, the device inner bore, the outer surface of the cutter and a stop flange limiting the stroke of the piston; the void is vented through a hole through the body of the guillotine, the guillotine being adjacent the void communicating between the void and the device internal conduit;

12. the body of the device may be a single tube section or may be more than one section assembled together, in which case the first section may comprise a wall and a flanged aperture for retaining the cutter and the piston retained by the locating means; the second portion may form a cylinder to surround and hold the disc, seal and vented central seat ring in place over the piston; the two parts can be assembled by the screw joint of the two parts to be mutually and hermetically attached;

13. when the body is a single component that holds the disc or discs as a sealing element, each end of the body is provided with threaded attachment means for attachment to and alignment within an associated wellbore tubular; this allows the assembly of the device without the seals being exposed to the harsh environment of the wellbore fluid, which is an important method of extending the useful life of the present device bore beyond state of the art pressure control devices with exposed seals (O-rings, etc.), without the need for expensive or complicated gas-tight threads or special materials;

14. the internal diameter of the internal bore of the body (i.e. its internal passage into which the piston fits) is slightly larger than the external diameter of the piston, while the gap between the two parts (body and piston) can be sealed against fluid communication using an O-ring or similar seal;

15. the device may include back-to-back frangible pressure retention disc seals, one or both of which are constructed as described above, but typically one with a cut-off as described above and one with a pressure frangible disc.

The invention also includes the use of the apparatus described herein above, comprising:

A. a method of operating a wellbore in a single-bore completion, comprising the following steps used with the apparatus of the present invention:

a. injecting a tubing string into a vertical portion of a wellbore;

b. adding the apparatus of the invention to a tubing string in a train;

c. further injecting the tubing string and devices included therein into the wellbore;

d. adding an annular packer or seal device to the tubing string and wellbore;

e. further injecting tubing, the device of the invention included therein and a packer or seal into the wellbore;

f. activating the packer or seal to seal the annulus between the tubular and the wellbore, thereby setting the packer at a desired depth in the wellbore and forming an annular seal;

g. fluid is injected into the disc of the invention under pressure which releases the positioning means of the device and causes the disc to strike the truncated piece of the device, causing the disc to rupture and open the pipe inside the pipe.

B. A method of operating a wellbore such that tubing and associated equipment float into a slanted lower portion of a slanted or horizontal wellbore, comprising the steps of:

a. adding a one-way removable seal as the device of the present invention to the bottom of the tubing string and injecting the tubing string into the wellbore with the high pressure side of the seal (including the convex side of the piston on the disc) facing the bottom of the wellbore;

b. the tubing string conduit is filled with a low density fluid, such as air or some non-condensable gas, and another one-way removable seal is added as the device of the present invention, with its high pressure side facing the bottom hole;

c. injecting a tubing string and a low density fluid included therein and two removable seal devices of the invention into the wellbore for a further predetermined distance, adding a high density fluid such as drilling fluid, water or a heavier fluid into the tubing string tubing above the highest seal device of the invention in the tubing string, providing gravity to assist in the injection of the tubing into the inclined or horizontal portion of the wellbore;

d. the tubing string is in the desired position in the well when the surface equipment is operated to apply sufficient pressure to the uppermost device to release the positioning means and rupture the disc seal by moving the piston so that the disc impacts the shear of the device;

e. in some cases, sufficient pressure is then continued to be applied to the oil conduit to release the positioning device and rupture the disc seal of the bottommost device of the present invention;

f. thus opening the pipeline (by step d or steps d and e) for further operation.

C. Similarly, the apparatus may be used to isolate a portion of a tubing string so that the portion may be filled with fluid during injection or other operations, thereby preventing collapse of the tubing in a high pressure well (known as a billit).

E. Similarly, a disc seal comprising two opposing discs of at least one apparatus of the invention may be used to isolate the setting of the packer and to pressure test the setting by first applying pressure from surface equipment to remove one disc to rupture the disc, then testing the packer, and then removing the second disc by further using pressure from the surface.

Drawings

FIG. 1a is a longitudinal section view or cross-section of a two-part body-style subassembly with an external field-refittable shear pin, ready for deployment in a well.

FIG. 1b is a cross-section of the subassembly of FIG. 1a, with the piston released and impacting the shear.

FIG. 1c is a cross-section of the subassembly of FIG. 1a with the pressure control frangible seal removed after impacting the cutout, and showing an open tubing flow path through the subassembly.

FIG. 1d is an exploded view of the operational components of the subassembly of FIG. 1 a.

Figure 2a is a cross-section of a dual frangible seal subassembly, one disc seal movable to open against a truncation, wherein the disc seal is retained by a second portion and a third portion of the subassembly secured to either end of a main portion of a body.

Fig. 2b is an exploded view of the components of the subassembly of fig. 2 a.

FIG. 3a is a cross-section of a sealless subassembly with two frangible disc seals, one disc with pressure retention on the moveable piston that can be adjusted in the field from inside the subassembly body.

Fig. 3b is an exploded view of the components of the subassembly of fig. 3 a.

Fig. 4a is a cross-section of another embodiment of a non-sealing subassembly similar to that shown in fig. 3 a.

Fig. 4b is an exploded view of the subassembly of fig. 4 a.

Fig. 5 shows two views, a top view and a side view, of the body of the mating ring (or mating locking ring).

Figure 6 shows two cross-sections of the piston, one for the externally mounted locating means 15a and the other for the piston mounted internally through ports or cut-outs in the wall 15 b.

Fig. 7 shows a cross-section of a tubular section with a vent hole and a sharp impact edge 15a and with an internal opening.

Figure 8 shows two variants of a shear pin that can be used as a locating means between the piston and the body of the subassembly.

Detailed Description

In wellbores that include tubulars, it is often desirable to isolate a portion of the pressure driven fluid flow path of the wellbore in the conduit section formed by the included tubulars to allow work to be done in the pressure control section of the flow path. The subassemblies and frangible devices provided herein achieve this with minimal exposure of the seal to the well's fluid environment, and provide field-adjustable variability in the pressure differential required to open the tubing by removing the frangible seal from the flow path in which the subassembly is installed or included.

For the reader's reference, legends for reference numbers in the following figures are provided:

a tubular body having a connection means enabling the body to be connected in line with an associated wellbore tubular;

1. a hollow piston slidably movable in the bore of the device body, the piston having a dynamic seal with the inner surface of the bore; the piston has features (lugs, holes, grooves) into which the locating means can extend or attach;

2. piston positioning means (which may be one or more shear pins that engage both the body of the device and the piston) that hold the piston in place until the pressure on one side of the piston exceeds a threshold pressure, wherein when the positioning means is released, the piston is slidably movable within a cylinder formed by the inner bore of the device;

3. a fracturable domed disc having a circular rim with a flange, the flange of the disc being disposed and sealed to one side of the piston, the body of the disc within the rim being exposed within an internal bore of the body of the device, dividing and partitioning the internal bore into two volumes, each volume being in fluid communication with a conduit in the wellbore tubing connected to one side or the other of the device; the disc is subjected on each side of the disc to fluid pressure exerted by fluid in a wellbore pipe connected to that (respective) side of the device;

4. the dome disk has a weakening on its body, which is located between: the connection between the edge of the concave round top surface of the disc main body and the inner surface of the flange; and a circumferential groove having a circumference approximately equal to an inner diameter of the flange portion disposed in the vicinity of a position where an edge of the convex rounded top surface intersects the flange outer surface;

5. a cutter disposed on the flange in the bore hole of the device on one side of the disc, facing the direction in which the piston can slide when the positioning device is released, wherein the cutter is shaped and positioned so that the surface of the disc in the flange hits the cutter when the piston and the disc attached thereto move after the positioning device releases the piston, thereby causing the disc to break by impact, causing the bore hole of the device body to become a flow conduit and ending the division of the inner conduit of the tube; the cutter is a cylindrical metal shape that can be fitted with a fluid discharge port at or near the end of the cutter that strikes the disk to allow any fluid discharged by the movement of the piston to escape through the discharge port into the central bore of the fitting body without impeding the movement of the piston;

6. the disc is retained, sealed and attached to the piston by at least one lo-hi seal on one side of the disc between the piston and the disc flange, and a vented center seat ring and a coupling ring threadedly attached to a bore in the device on the other side of the disc; the joint ring is provided with an inner opening, and the inner diameter of the joint ring is slightly larger than the outer diameter of the cutting piece;

7. alternatively, the body of the device may be in multiple parts that can be disassembled and reattached, whereby attachment of one part can retain and seal the disc, lo-hi seal, and vented center seat ring to the piston, while the connection between the parts of the body assembly functions as a mating ring;

8. upon rupture of the disc, its flange is sandwiched between the outer surface of the cutter, the recessed inner surface of the bore and the radial surface of the mating ring to prevent the portion of the frangible disc seal body from entering the conduit of the wellbore formed within the pipe; a thin-walled steel ring may be inserted into the flange of the disc and sized to allow the guillotine to strike the disc body, but in addition to isolate the ceramic flange portion of the disc seal, capturing and holding the ceramic flange portion away from the inner bore of the tube and the tube flow passage after the disc breaks (due to being struck by the guillotine edge);

9. the positioning device is field adjustable without completely disassembling the downhole device by changing the amount of force applied before the positioning device releases the piston (this can be done through an external port on the body or through the piston wall and into an internal port of the device body by changing the number or composition of shear pins installed to hold the piston in position with the device body); a shear pin, for example, may be inserted from the outer surface of the body, extending inwardly through the body and into a mating aperture (groove, bore) located on the radially outer surface of the piston; if inserted from the outside, the piston may be inserted and mechanically sealed to the body by friction (e.g., the pin may be slightly tapered to wedge into a mating hole of the body, deform and seal to the body by being forced into place); alternatively, the pin may be threaded, screwing into mating threads on the body wall and a groove or aperture on the piston;

10. a space or volume exists in the inner bore of the body into which the piston can move when sliding after release of the positioning means, the space or volume being outside the outer surface of the cutter and thus being bounded by the end of the piston remote from the disc, the device inner bore, the outer surface of the cutter and a stop flange limiting the travel of the piston; the void is vented through a hole through the body of the guillotine, the guillotine being adjacent the void communicating between the void and the device internal conduit;

11. the body of the device may be a single tube section or may be more than one section assembled together, in which case the first section may comprise a wall and a bore with a flange for holding the cutter and the piston held by the locating means; the second portion may form a cylinder to surround and hold the disc, seal and vented central seat ring in position over the piston; the two parts can be assembled by the screw joint of the two parts to be mutually and hermetically attached;

12. when the body is a single part holding the disc or discs as a sealing element, each end of the body is provided with threaded attachment means for attachment to and alignment within an associated wellbore tubular; this allows the assembly of the device without the seals being exposed to the harsh environment of the wellbore fluid, which is an important method of extending the useful life of the present device bore beyond state of the art pressure control devices with exposed seals (O-rings, etc.), without the need for expensive or complicated gas-tight threads or special materials;

13. the bore of the body (i.e. its internal passage into which the piston fits) has an internal diameter slightly larger than the external diameter of the piston, while the gap between the two parts (body and piston) can be sealed against fluid communication by means of an O-ring or similar seal;

14. the device may include back-to-back frangible pressure retention disc seals, one or both of which are constructed as described above, but typically one with a cut-off as described above and one with a pressure frangible disc.

h. injecting a tubing string into a vertical portion of a wellbore;

i. adding the apparatus of the invention to a tubing string in a train;

j. further injecting the tubing string and devices included therein into the wellbore;

k. adding an annular packer or seal device to the tubing string and wellbore;

injecting further tubing, the device of the invention included therein and a packer or seal into the wellbore;

actuating the packer or seal to seal the annulus between the tubular and the wellbore, thereby setting the packer at a desired depth in the wellbore and forming an annular seal;

n. fluid is injected into the disc of the invention under pressure which releases the device positioning means and causes the disc to impact the shear of the device, causing the disc to rupture and open the pipe inside the pipe.

c. injecting a tubing string and low density fluid included therein and two removable seal devices of the invention into the wellbore a further predetermined distance, adding a high density fluid such as drilling fluid, water or a heavier fluid into the tubing string tubing above the highest seal device of the invention in the tubing string, providing gravity to assist injection of the tubing into the inclined or horizontal portion of the wellbore;

d. the string is in the desired position in the well, at which time the surface equipment is operated to apply sufficient pressure to the uppermost device to release the positioning means and rupture the disc seal by moving the piston so that the disc impacts the guillotine of the device;

As an example of the inventive arrangement, a field adjustable pressure subassembly 1 is provided in fig. 4a and 4b, which comprises the following parts: the subassembly body 6, into which the tubular section 15 fits and rests on the flange (requiring reference numbers) of its blunt end. The cylindrical piston 30b fits over the outer surface of the cutout and partially into the bore of the body 6 until the entry port 23 in the cutout is aligned with the socket 45, thereby receiving the shear pin 45 (the second shear pin reference for the pin corresponding to the socket). The burst disc subassembly of the lo-hi seal (), the disc (), the center seat ring (), and the adapter ring 55 are assembled in sequence into the subassembly body 6 so that the disc subassembly () rests on it and is held in place by the piston edge furthest from the sharp strike edge () of the cutter.

To adjust the strength or retention of the positioning device, in this example, shear pins of different shear characteristics, or screws may be removed, installed, or reinstalled in the field by loosening the engagement ring 55 and removing the components of the burst disk subassembly () in the order of engagement ring 55, center seat ring (), and disk (): thereby adjusting, replacing, moving, placing or replacing the shear pin by means of a hole through the assembly body 6 inside the guillotine 15 and the piston 30b and the access port 23 directly to the shear pin position 23. The subassembly can then be reassembled (assembly steps in reverse order).

Similarly, the field adjustable pressure subassembly 1 of fig. 1a provides field adjustable force or holding power (a maintained pressure differential until a pre-designed desired pressure differential is applied to the slidable disc/piston 2) by way of example, by an operator retrofitting, replacing or removing the shear pin 45 from the outer surface of the subassembly. The piston 30a in this example will have an external feature (in this case a circumferential groove () or slot) on its outer circumferential surface into which the shear pin 45 can be inserted from outside the subassembly body, thereby interfering with the action of the piston until the shear pin is sheared. Once sheared, the second shear pin guide groove may receive the deformed shear pin material such that the sliding action of the piston is not affected.

It will be appreciated that the inner diameter of the disc flange () is slightly larger than the outer diameter of the cut end () of the guillotine 15 and that the guillotine 15 should have been struck by the disc () with a designed weakened portion of the disc body as described above.

Claims

1. A pressure control device comprising:

a tubular body having connection means such that the body can be connected in line with a wellbore tubular at an interface;

a hollow piston slidable in a bore of the body, the piston and an inner surface of the bore having a dynamic seal therebetween;

the piston has features into which the locating means may extend or attach, including one or more lugs, holes or recesses;

the positioning means being field-accessible without substantial disassembly of the apparatus for holding the piston in position until the pressure on one side of the piston exceeds a threshold pressure;

the piston is slidably movable in a cylinder formed by the bore when the positioning means is released; and

a disc frangible and having a circular rim, a disc flange, a domed surface, the disc flange coupled to one side of the piston, at least a portion of the disc exposed to the inner bore, the disc dividing the inner bore into two volumes, each volume in fluid communication with the inner conduit of the wellbore tubular, the disc bearing on each side a fluid pressure exerted by fluid in the wellbore tubular at the interface.

2. The device of claim 1, wherein

The disc having a weakened portion in the body at the junction of the circular edge of the disc and the disc flange; and

the disk has a circumferential groove with a circumference approximately equal to the inner diameter of the disk flange, the disk flange being disposed adjacent to where the dome surface contacts the outer surface of the disk flange.

3. The apparatus of claim 1, further comprising:

a cutout disposed on an internal flange in said bore, wherein said cutout has a disk cut shape at one end toward a side of said disk that is toward a direction in which said piston is slidable when said positioning device is released; and

the positioning of the guillotine is such that when the positioning means releases the piston, the piston and its attached disc are forced to move, while the surface of the disc in the disc flange hits the cut shape of the guillotine, the disc thereby breaking, allowing fluid communication between the two sides of the device through the inner bore.

4. The device of claim 3, wherein the cutout includes one or more fluid vents proximate an end of the cutout opposite the end with the cutting shape for rupturing the disc, the fluid vents allowing expelled fluid to escape into the central bore by movement in the cylinder of the bore when the piston and disc are released.

5. The apparatus of claim 1, wherein the disc is coupled to the piston by at least one lo-hi seal on one side of the disc and between the piston and the disc flange; the apparatus further includes a vented center seat ring, and an adapter ring threadably attached to the inner bore on a second side opposite the first side of the disk flange; the adapter ring has an inner opening with an inner diameter greater than the outer diameter of the cutout.

6. The device of claim 1, wherein

The disc is coupled to the piston by at least one lo-hi seal on one side of the disc between the piston and the disc flange; the device further comprises a central seat ring with vent holes; and

the body is made of multiple parts that can be disassembled and reassembled at one or more connections, and the attachment of one such part can hold and seal the disc, the lo-hi seal, and the vented center seat ring to the piston.

7. The device of claim 5 wherein when the disk is ruptured, the disk flange is sandwiched between the cutout, the concave inner surface of the bore, and the radial surface of the adapter ring.

8. The apparatus of claim 2 wherein the disc flange comprises a ring sized to allow the guillotine to strike the body of the disc while preventing at least a portion of the rupture disc from entering the wellbore tubular.

9. The device of claim 2, wherein the guillotine and the disc collide, the entire disc breaking and being removed.

10. The device of claim 1, wherein the positioning means comprises one or more pins engageable with the body and the piston, the device body having a tool access port associated therewith, such that the associated pin can be removed, replaced or retrofitted through the associated access port on the body.

11. The apparatus of claim 1, further comprising a space into which the piston can move after the positioning device is released.

12. The device of claim 1, wherein the body is made of multiple parts that can be coupled together.

13. The apparatus of claim 5, wherein the body is made of multiple parts that can be coupled together, a first part of the multiple parts comprising a wall, a bore and an internal flange, and a second part of the multiple parts comprising a cylindrical shape to hold the disc, lo-hi seal and vented center seat ring in place relative to the piston.

14. The apparatus of claim 1, further comprising attachment means at both ends of the apparatus for attachment to the wellbore tubular.

15. The apparatus of claim 1, wherein the inner bore has an inner diameter greater than an outer diameter of the piston to define a gap between the body and the piston, further comprising a seal in the gap.

16. The device of claim 1, further comprising a second disk, wherein the cutout is configured to impact the first disk and the second disk is configured to be frangible under pressure.

17. A method of pressure control using the apparatus of any one of claims 1-16, comprising:

injecting a tubing string into a vertical portion of a wellbore;

adding the devices in a column into the tubing string;

injecting the tubing string and the device further into the wellbore;

adding a packer to the tubing string;

injecting the tubing, the device, and the packer further into the wellbore;

activating the packer to seal an annulus between the tubular and the wellbore, thereby setting the packer at a desired depth in the wellbore and forming the annular seal; and

fluid is injected into the disc of the invention under pressure which releases the positioning means of the device and causes the guillotine to impact the disc, causing the disc to rupture and opening the internal duct of the tube.

18. Method for pressure control with two devices according to any of claims 1-16, comprising:

adding a first of the two devices to the bottom of a tubing string and injecting the tubing string into the wellbore with the convex side of the disc toward the bottom of the wellbore;

filling the tubing string with a low density fluid and adding the second of the two devices to the tubing string that has entered the wellbore with the convex side of the disc toward the bottom of the wellbore;

injecting the tubing string into the wellbore a further predetermined distance and adding a high density fluid into the tubing string above the uppermost of the two devices; and

the tubing string is positioned at a desired location in the well at which time surface equipment is operated to apply sufficient pressure to the uppermost device to release the positioning means of the uppermost device, thereby rupturing the disc.

19. The method of claim 18, further comprising continuing to apply sufficient pressure in the conduit to release the positioning means of the lowermost device.